The present invention relates to an apparatus for rotating and traversing the slats in a vertical blind and particularly to improvements in the vertical blind with louver rotation control disclosed in U.S. Pat. No. 4,936,369, assigned to the assignee of the present invention. The '369 patent discloses a vertical blind of the type having a plurality of louver carriages mounted for movement along a guide channel, with a louver carrier mounted on each carriage for rotation about an upright axis and carriage gear mechanism for rotating the louvers in response to turning of an operating shaft that extends lengthwise of the channel, and a wand operated mechanism for turning the operating shaft in response to raising and lowering of a wand. The wand operated mechanism included a drive lever pivotally mounted on a housing at one end of the guide channel with one end of the drive lever adjacent one side of the channel and a wand attached to that end and extending downwardly therefrom for oscillating the drive lever through a first angle in response to upward and downward movement, and angular motion transmitting means interconnecting the drive lever and the operating shaft and operative in response to angular oscillation of the drive lever through the first angle to oscillate the operating shaft through a second angle substantially greater than the first angle. The carriage gear mechanisms on the louver carriages were constructed and arranged to rotate the associated louver carrier through an angle of substantially 180.degree. in response to rotation of the operating shaft through the second angle. The wand was tubular and one of the operating cords for traversing the cords along the carrier guide channel extended through the tubular wand to separate the traverse cords an facilitate traversing of the carriage along the channel. In addition, the drive lever was arranged so that it could be reversibly mounted on the housing to enable positioning of the wand at either side of the channel, to adapt the blind for operation at either the left hand or the right hand of the blind.
In this prior apparatus, the louvers sometimes rotated from a previously adjusted position in response to a draft or breeze blowing against the louvers. In addition, the louvers sometimes rotated from an adjusted position when the operating cord was pulled in one direction or the other to traverse the slat carriers along the channel. Further, the wand in the prior apparatus was offset from the front side of the channel in all operating positions of the wand, and this not only adversely affected the appearance of the vertical blind but also caused the traverse cords to extend at a substantial angle as they entered the upper end of the wand.